The present invention relates to weatherproofing membranes and in particular, to a weatherproofing membrane having a high traction surface.
Weatherproofing membranes are commonly used in roofing and other similar applications. The membrane is usually applied to the roof or other such structure to provide weatherproofing. Such membranes typically include a substrate or facer sheet made of a polymer, such as polyethylene, that has an inherently slippery surface. The slippery upper surface of these materials creates a hazard both for the workers applying the membranes and also to any other individual climbing or walking on the slippery polymer surface of the weatherproofing membrane.
Accordingly, a need exists for a weatherproofing membrane having a high traction surface.
The present invention features a weatherproofing membrane comprising at least one facer sheet having an upper side and a lower side and being formed of a weatherproofing material. At least one layer of polymer is disposed on at least one region of the upper side of the facer sheet to provide a higher traction than the weatherproofing material. In one embodiment, the region with the polymer includes a plurality of stripes of the polymer disposed on the upper side of the facer sheet. At least one layer of modified asphalt is disposed on at least a portion of the lower side of the facer sheet. The weatherproofing membrane can also include a release backing releasably disposed over the layer of modified asphalt.
The polymer preferably includes a mixture of at least a low molecular weight polyethylene and an amorphous polyolefin. The proportion of low molecular weight polyethylene to amorphous polyolefin ranges from about 50/50 to 90/10. In one preferred embodiment, the mixture includes about 75% of the low molecular weight polyethylene and about 25% of the amorphous polyolefin. One example of the amorphous polyolefin is a polypropylene/propylene-ethylene copolymer resin mixture.
The weatherproofing membrane is preferably a plastic film, such as a high density cross-laminated polyethylene film or a straight high density polyethylene film.
The modified asphalt is preferably a polymer modified asphalt composition. The softening point of the polymer used for the high traction surface is preferably greater than a softening point of the modified asphalt.
The present invention also features a method of making a membrane having a high traction polymer surface. The method comprises the steps of: hot mixing a quantity of amorphous polyolefin with a quantity of low molecular weight polyethylene to form a polymer blend; and applying the polymer blend to at least a portion of the membrane. The hot mixing can be performed in a hot mix tank or an extruder and is preferably performed in a temperature range of about 300xc2x0 F. to 400xc2x0 F.